hidpi.spec.js

/**
 * @fileoverview Tests for window.devicePixelRatio > 1.
 *
 * @author danvdk@gmail.com (Dan Vanderkam)
 */
describe("hidpi", function () {

var savePixelRatio;
beforeEach(function () {
  savePixelRatio = window.devicePixelRatio;
  window.devicePixelRatio = 2;

  document.body.innerHTML = "<div id='graph'></div>";
});

afterEach(function () {
  window.devicePixelRatio = savePixelRatio;
});

it("testDoesntCreateScrollbars", function () {
  var sw = document.body.scrollWidth;
  var cw = document.body.clientWidth;

  var graph = document.getElementById("graph");
  graph.style.width = "70%";  // more than half.
  graph.style.height = "200px";

  var opts = {};
  var data = "X,Y\n" +
          "0,-1\n" +
          "1,0\n" +
          "2,1\n" +
          "3,0\n"
      ;

  var g = new Dygraph(graph, data, opts);

  // Adding the graph shouldn't cause the width of the page to change.
  // (essentially, we're checking that we don't end up with a scrollbar)
  // See http://stackoverflow.com/a/2146905/388951
  assert.equal(cw, document.body.clientWidth);
  assert.equal(sw, document.body.scrollWidth);
});

});